Electro-photographic image forming apparatuses can form an electrostatic latent image by scanning light beams onto a photosensitive surface of a drum using a light scanning unit, can develop the electrostatic latent image using a developing agent, such as toner, to generate a toner image, can transfer the toner image onto a print medium, and can fix the toner image to the print medium.
A light scanning unit in a conventional image forming apparatus typically uses a polygon mirror driven by a spindle motor. There has been a recent demand, however, for a substitute for light scanning units using a polygon mirror that can overcome current limitations in the speed of the polygon mirror, that need not include a spindle motor so as to remove a source of noise generated during high speed operation, and that is small enough such that the size of the light scanning unit can be reduced.
A light scanning unit using a micro electro-mechanical system (MEMS) structure can be used to overcome limitations associated with light scanning units that use polygon mirrors. MEMS structures can allow for bidirectional scanning and high speed scanning, and can be made sufficiently small when fabricated by a semiconductor process. MEMS structures can be particularly useful in light scanning units that can scan multiple light beams, such as those used to form a color image. A MEMS double-sided mirror scanner can be advantageous in that a MEMS double-sided mirror scanner can scan multiple light beams concurrently by rotationally oscillating a double-sided mirror.